Some Geometry for the Woods...

Sulaco

Sulaco

Gold Member
Joined
Nov 15, 2003
Messages
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Sorry, no pictures but I can at least share my findings.

I do a fair bit of outdoor stuff - anything from day hikes to overnight trips, hunting, fishing, camping and everything in between. I've always had and used knives and found over the last few years that blade/edge geometry seems to make more of a difference (for me anyway) than steel type or hardness, etc when it comes to wood.

So I decided to do a little informal testing. I cut a 2" thick sweetgum sapling and have been letting it dry for a few months now. It stays quite wet in my area so "dry" is a relative term. It's not green anyway, but certainly nothing close to well-seasoned oak or hickory.

Anyway, I have the following knives I used to do some simple notches, just to test how many cuts and how much pressure was needed to push through the bark, wood and heartwood of the sapling:

Bark River Bravo Necker II (CPM-3V, 7" overall, 3.25" blade, .130" thick) w/ Micarta scales - 8 cuts until I reached the heartwood, strong pressure

Bark River Bravo-1 (rampless, A2, 9.065" overall, 4.25" blade, .215" thick) - 3 cuts until I reached the heartwood, very light pressure

Bark River Gunny (rampless, A2, 8.4" overall, 3.775" blade, .156" thick) - 5 cuts until I reached the heartwood, light pressure

Bark River Aurora (CPM-3V, 9.5" overall, 4.5" blade, .170" thick) - 2.5 cuts until I reached the heartwood, very light pressure

Mora 911 (Swedish carbon steel, ? overall, 4" blade, .098" thick) - 6 cuts until I reached the heartwood, light-medium pressure

ESEE Candiru (1095, 5.13" overall, 2" blade, .125" thick) w/ Micarta scales - 15 cuts until I reached the heartwood, very strong pressure

Blind Horse Knives Boattail Scandi (O1, 7.75" overall, 3.25" blade, .125" thick) - 9 cuts until I reached the heartwood, strong pressure

Benchmade RSK Mk1 Ritter Griptilian (S30V, 8.06" overall, 3.44" blade, .115" thick) - 10 cuts until I reached the heartwood, strong pressure

Benchmade Contego (CPM-M4, 9.28" overall, 3.98" blade, .156" thick) - 8 cuts until I reached the heartwood, strong pressure

Wetterlings Wildlife Axe (Swedish carbon steel, 5.5" overall, 2.5" blade, ? thick) - 5 cuts until I reached the heartwood, medium pressure

To make things simple, the convex ground A2 and CPM-3V from Bark River absolutely destroyed everything else I tried. In fact, the Bravo-1 and the Aurora worked so well, I was quite astonished to be honest.

The Wetterlings hatchet with it's convex edge also worked really well, but the less wide Aurora worked the best.

After the two Bark Rivers and the Wetterlings, (well, and after all of the other Bark Rivers), the next best was the Mora. At first I noticed the edge rolled some, but once I re-sharpened it (using a true Scandi grind), it worked well - although nowhere near as well as the Barkies.

The convex grinds seems to work tremendously well in wood, especially in these notch-cutting tests. I also find they work really well stripping bark, making fuzz sticks and other similar tasks. I thought the Scandi grinds would do better, but it seems they only work well if the blade is ground thin. I love the ergonomics of the Boattail Scandi, but it's way too thick to be useful, even compared to the 15 dollar Mora 911. Compared to the Bark River convex edges, even the crazy thick Bravo-1, it's just no comparison.

The Benchmade Ritter in S30V did okay for a folder, but even though it's thin, the v-grind hurt it. I bet if it was convexed, it would do really well. The Contego in CPM-M4 did pretty good even with it's v-grind. I think that M4 is good stuff and might convex that one as well.

I love Rowan's heat treat on TOPS and ESEE knives and the Candiru is no exception. But it's so small, it took an immense amount of pressure just to get in the wood good, and the v-grind hurt it. It did keep it's edge really well though, no rolling or chipping at all and still shaving sharp afterwards.

Folks, Mike Stewart and crew at Bark River obviously know what they are doing when it comes to edge/blade geometry and hardness in the steels they are using. I could not tell a bit of difference in edge retention between the A2 models and the CPM-3V models. Now I am sure if I was using them to clean game it would be apparent how much better edge retention the 3V has, but in wood, hard or soft, I can't tell any difference.

Anyway, I hope this info helps someone making decisions about bushcraft/outdoors knives!
 
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A while back I decided to buy a BHK Bushcrafter and I did all the research possible on convex vs scandi. The results youve posted sound exactly like what Mike Stewart was saying on another forum, he added that thats why Bark River and Fallkniven are the best production knives. I bought a convex BHK and since then a Fallkniven F1 also, I think convex cuts the best and the deepest but scandi or V grind are easier to control angles when shaving or slicing bark. YMMV :thumbup:
 
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I didn't know BHK was doing convex grinds. Are they full-height? Which knife model is it?

I like Fallkniven but the convex grinds on the ones I've tried are too thick or something. I'm not sure what it is about them, but they just don't cut as deep as my Barkies.

I agree about shaving bark, but it only matters to me if the diameter of the wood is big enough around to benefit. Otherwise, they are a toss-up from what I've found.
 
No well at that time(1.5 years ago) I didnt know the difference between a convex edge and a convex grind. I still find my ffg convex edge bushcrafter cuts better than my ffg v izula, and anything I sharpen on my worksharp cuts better than any v bevels. Convex helps at every level.
 
I use my WorkSharp to set convex bevels also. I had a FFG Delica that cut like a demon with a convex edge.
 
I completely agree. It's a hallmark of an ignoramus to think otherwise. I don't know what they think is happening – like the material to be cut detects what kind of steel it is and runs away when it is beyond a certain threshold. Sure, I can think of extreme exceptions like a blade made from something so crap it just collapses and mashes when you try to cut, but even very cheap knives don't unless they really are made from such hypothetical bean tin material.................It's inescapable that it is the shape that determines how well a knife cuts. What it is made from, along with the heat treatment, determines how long it will keep doing it...............This touches on a pet amusement of mine. I see a lot of knives made from cooed over steel but the shapes make them pathetic cutting instruments. All the steel does in that implementation is ensure they stay that miserable shape for longer than they otherwise would.
 
Interesting comparison - it would be great to have detailed specs on the physical geometries for each for intellectualizing.

FWIW on A2 vs. S30V, I cleaned and disassembled an entire deer this past season with a 3" A2 blade. It never dulled. The only reason it stopped cutting was because the edge got sticky with dried stuff. It needed cleaning, not sharpening. You'd have to clean a LOT of game to discover the difference in edge retention between the two - or perhaps you could just cut on a lot of hide from the outside. :D
 
daizee said:
Interesting comparison - it would be great to have detailed specs on the physical geometries for each for intellectualizing.

FWIW on A2 vs. S30V, I cleaned and disassembled an entire deer this past season with a 3" A2 blade. It never dulled. The only reason it stopped cutting was because the edge got sticky with dried stuff. It needed cleaning, not sharpening. You'd have to clean a LOT of game to discover the difference in edge retention between the two - or perhaps you could just cut on a lot of hide from the outside. :D
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I can list the specs of each one but I don't have a micrometer to measure things like cross-section widths and all.

Yeah I think nicking bone and cutting hide is what dulls them the most for me.
 
Sulaco said:
I can list the specs of each one but I don't have a micrometer to measure things like cross-section widths and all.

Yeah I think nicking bone and cutting hide is what dulls them the most for me.
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Nah, it's really hard to measure width at the bevel and bevel height, even with a mic. There are probably some very specialized tools that could do it, but it would be a huge pain. then you'd have to render each one in CAD to compare them visually too. ;)
 
I've found that the thinness of the edge combined with the shape of the blade is more important than the grind. For instance a thin ground knife with a gradual belly that carries through most(or conitinuous throughout) of the blade to be the best. My guess is that this type of blade contacts the wood at a point instead of across a long length of a straight edge which concentrates the force in a single spot imparting more pressure. More pressure equaling more cutting power. For me the grind is mostly not a concern given the other criteria. Though I do prefer convex. ;)
 
Great thread. We need more of this. I'm suffering from post repetition burn out. Thanks brother.
 
The more I use the Aurora, the better I like it. CPM 3V really lets BR maximize their grinds for cutting. The only knife in their lineup that might blow it away is the Northstar. Nice thin FFG. Combined with 3V, it's almost perfect. Until I find the next knife... ;)
 
I liked the Northstar pretty good, but much prefer the almost full-height convex of the Aurora than the FFG Northstar. It did make for an awesome slicer though! I also prefer the "ergonomic" style grips on Barkies, like those on the Aurora and Bravo/Gunny. I wish the grip on the Highland was a little longer because I really like that knife but being short and squared off, I get hot spots using it.

I added the specs of the knives I tested to the original post.
 
Oh one thing I forgot to add, I wish BHK would do a Boattail style knife but with a full-height convex grind. That would be almost the perfect "bush" knife for me. The size, ergonomics and steel are really good and the overall design would really work well with a convex grind. I thought about having someone re-grind the Scandi, but decided to move it along and buy something else. I wonder how it would have done though?
 
Sulaco said:
I wish the grip on the Highland was a little longer because I really like that knife but being short and squared off, I get hot spots using it.
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The Highland is a very pretty blade. The squared-off handle shape is VERY easily fixed... It's like BRKT simply stopped the handle shaping/contouring process a little early.
 
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